Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
va thanh » gia thanh, ban thanh, va tinh
hieu van » hieu va, thien van, lieu va
chau tre » chay tren, chau tho, cho tre
ly vang » ly hang, ly van, ly quang
van cac » van hac, van cau, van bac
cac luc » cau luc, coc luc, cac nuoc
va hanh » van hanh, va danh, ban hanh
ly nang » ky nang, ly hang, ly quang
x hoi » xa hoi, o hoi, x ho

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ((ly nang) or (ly vang)) x hoi. hieu van cac luc ((va hanh) OR (va thanh)) lai chau tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((ly nang) OR (ly vang)) x hoi. hieu van cac luc ((va hanh) OR (va thanh)) lai chau tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((ly nang) or (ly vang)) x hoi. hieu van cac luc ((va hanh) OR (va thanh)) lai chau tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ((ly nang) or (ly vang)) x hoi. hieu van cac luc ((va hanh) OR (va thanh)) lai chau tre*.